In the Internet information search field, full-text keyword search and structured information search are two most frequently used search methods. An advantage of the full-text keyword search is good search completeness, and a disadvantage is low search accuracy (referring to FIG. 1). An advantage of the structured information search is good search accuracy, and a disadvantage is search incompleteness. The problem that complete information search and accurate information search cannot be implemented concurrently not only restricts efficiency of comprehensive search of Internet information, but also directly causes a user searching for information to switch frequently between the full-text keyword search and search of various types of structured information. Therefore, how to substantially solve the problem that the complete information search and the accurate information search cannot be implemented concurrently is always the most important topic in the Internet information search field.